Now, to the big custody t over obee. The dieting dachshund has made him a national sensation. An animal rescue group is going to court to try to take obee away from the woman who took him in. Neal karlinsky has the story. Reporter: There's fat pets. Then, there's obee. The 5-year-old dachshund tips the scales at a what happening 77 pounds. Nora says she agreed to temporarily adopt him to help with his weight. But she quickly fell in love and realized others were interested, too. Hi, obee. Hi, obee. Reporter: She's traveled the country with obee, to make tv appearances and set up a facebook page. It has more than 66,000 followers. People came to see obie. And obie was inspiring them to lose weight. Talk to us. Reporter: He's now the center of a bitter custody dispute in an oregon court. The agency claiming to be his owner, oregon dachshund rescue, claims obie is being wrongfully held by the defendant, who is exploiting the dog for the sensationalistic promotional value of its unusual obesity. Translation? They want the dog back because they think she is trying to get famous and pocket the donations that are now flowing in. The money just sit there's because he may need to have surgery to have the excess skin removed. Reporter: She says obie has lost 15 pounds and is doing better. Who gets him? A judge will decide on monday, when obie goes to court. For "good morning america," neal karlinsky, abc news, seattle.

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